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PLASTIC FLOW AROUND AN EXPANDING CRACK

The problem of a central crack expanding at both ends in a uniformly stretched plate is examined for the case when the material along the lines of expected crack extension flows plastically and moves with the crack at a different velocity. The variations of the plastic zone size with crack speeds and applied stress to yield stress ratio P/Y are determined. For a given value of P/Y, and increase in crack velocity is found to cause a decrease in the length of the traveling plastic zone. The amount of energy released by the moving crack is also estimated for the purely elastic and elastic-plastic crack models and is shown to diminish to zero at the Rayleigh wave speed. The present results support the expected conclusion that for a given amount of available energy a crack can be driven at a high speed without plastic dissipation. This effect is demonstrated quantitatively for the strip model of an expanding crack.

Corporate Authors:

Lehigh University

Institute of Fracture and Solid MechanicsBethlehem, PA
United States
18015